(The density given includes charge on both sides of the sheet). What is the magnitude of the electrical force on each sheet, in N/m^2

Answers are 3.2pi, 1.4pi and 1.8pi.

2. Relevant equations
For an infinite plane, the electrical field strength is:

σ/2ε where ε is 8.85 * 10^-12 and σ is charge density.

Also, Force = Electric Field * Charge

3. The attempt at a solution
dF = EΩdA or
dF/dA = EΩ where Ω is the charge density of the plane whose force is being calculated

(Can someone verify if this line of reasoning is correct?):

The electric field for any patch of area on A should be the average of the electric fields above and below. This comes out to simply be the superposition of the electric fields generated by sheets B & C because the electric field generated by A cancel out on both sides.

EDIT: So I did a quick test to check something. Apparently if I subtract the two density charge contributions for the electric field for Sheets A & C, I get the right answer but this has only made sense for Sheet B because the electric fields were in opposite directions. For Sheet A, the electric fields are both pointing down towards B & C while for Sheet C, the electric fields are both pointing up towards A & B.

Also, I'm curious as to why the answers have pi in it. All my calculations simply didn't require it. Is there another way to do this?